CVE-2026-54003: Getkirby Kirby

Critical severity, CVSS 9.1. EPSS: 0.7% chance of exploitation in the next 30 days.

Kirby is an open-source content management system. Prior to 4.9.4 and from 5.4.4, Kirby sites with no configured user accounts that run on publicly accessible servers behind a reverse proxy setting the Forwarded, X-Client-IP, or X-Real-IP request header could allow remote attackers to install the Panel and create the first admin user because local-IP checks trusted those headers incorrectly. This issue is fixed in versions 4.9.4 and 5.4.4.

Affected products

• Getkirby Kirby: before 4.9.4 (fixed in 4.9.4); from 5.0.0, before 5.4.4 (fixed in 5.4.4)

Published 2026-07-09. Last modified 2026-07-10.